LABORATORY RESEARCH Bcl11a Is Essential for Lymphoid Development and Negatively Regulates p53 Scientists report that, in the adult mouse, Bcl11a is expressed in most hematopoietic cells and is highly enriched in B cells, early T cell progenitors, common lymphoid progenitors, and hematopoietic stem cells. [J Exp Med] Abstract Pharmacological Stabilization of HIF-1α Increases Hematopoietic Stem Cell Quiescence In Vivo and Accelerates Blood Recovery following Severe Irradiation To investigate the effects of hypoxia on hematopoietic stem cells, the authors blocked O2-dependent hypoxia-inducible transcription factor (HIF)-1α degradation in vivo in mice by injecting two structurally unrelated prolyl hydroxylase domain enzyme inhibitors: dimethyloxalyl glycine and FG-4497. [Blood] Abstract A Novel Role of BMP4 in Adult Hematopoietic Stem and Progenitor Cell Homing via Smad Independent Regulation of Integrin-α4 Expression Scientists described a novel mechanism by which BMP4 regulates homing of murine as well as human hematopoietic stem/progenitor cells. BMP4 treatment of murine bone marrow derived c-kit+Lin–Sca-1+ (KLS) and CD150+CD48–KLS cells for up to five days in vitro prevented the culture-induced loss of Integrin-α4 expression as well as homing. [Blood] Abstract Signaling Axis Involving Hedgehog, Notch, and Scl Promotes the Embryonic Endothelial-to-Hematopoietic Transition In differentiating mouse ES cells and mouse yolk sac cultures, addition of Indian Hedgehog (Hh) ligand increased hematopoietic progenitors, whereas chemical inhibition of Hh signaling reduced hematopoietic progenitors without affecting primitive streak mesoderm formation. [Proc Natl Acad Sci USA] Abstract Cell of Origin Determines Clinically Relevant Subtypes of MLL-Rearranged AML MLL-AF9 transduced single hematopoietic stem cells (HSC) or granulocyte macrophage progenitors (GMP) could be continuously replated, but HSC-derived clones were more likely than GMP-derived clones to initiate acute myeloid leukemias (AML) in mice. [Leukemia] Abstract Sulforaphane Induces Cell Cycle Arrest and Apoptosis in Acute Lymphoblastic Leukemia Cells Researchers report that purified sulforaphane, a natural isothiocyanate found in cruciferous vegetables, has anti-leukemic properties in a broad range of acute lymphoblastic leukemia (ALL) cell lines and primary lymphoblasts from pediatric T-ALL and pre-B ALL patients. [PLoS One] Full Article | Press Release Donor Hematopoietic Stem Cells Confer Long-Term Marrow Reconstitution by Self-Renewal Divisions Exceeding to That of Host Cells Dormant hematopoietic stem cells are activated by microenvironmental cues of the niche in response to the injury of bone marrow. It is not clearly understood how engrafted cells respond to these cues and are involved in marrow regeneration. Scientists aimed to decipher this cellular response in a competitive environment. [PLoS One] Full Article Avoiding Room Temperature Storage and Delayed Cryopreservation Provide Better Postthaw Potency in Hematopoietic Progenitor Cell Grafts Researchers aimed to determine the influence on cell potency of thawed products from three sources of hematopoietic progenitor cells after prolonged storage at different temperatures before cryopreservation. [Transfusion] Abstract CLINICAL RESEARCH Cord-Blood Engraftment with Ex Vivo Mesenchymal-Cell Coculture Poor engraftment due to low cell doses restricts the usefulness of umbilical-cord-blood transplantation. Researchers hypothesized that engraftment would be improved by transplanting cord blood that was expanded ex vivo with mesenchymal stromal cells. [N Engl J Med] Abstract | Press Release Impact of Age on Outcomes after Initial Therapy with Chemotherapy and Different Chemoimmunotherapy Regimens in Patients with Chronic Lymphocytic Leukemia: Results of Sequential Cancer and Leukemia Group B Studies Researchers examined patients enrolled onto successive first-line CALGB chronic lymphocytic leukemia trials to determine whether efficacy of regimens varied by age, focusing on ideal chemotherapy choice and benefit of immunotherapy addition to chemotherapy in older patients. [J Clin Oncol] Abstract | Press Release |